A man can row 30 km upstream and 44 km downstream in 10 hours. Also, he can row 40 km upstream and 5

Sourojit Dhua   10 years AGO

Let rate upstream = x km/hr
and rate downstream = y km/hr.
Then,40/x +55/y = 13...(i)
and 30/x +44/y = 10
Multiplying (ii) by 4 and (i) by 3 and subtracting ,we get:11/y = 1 or y = 11.
Substituting y = 11 in (i),
we get: x = 5.
Rate in still water =1/2(11+5) kmph = 8 kmph.
Rate of current=1/2(11-5)kmph = 3 kmph

Like? Yes (55) | No (21)  

rajan kumar   10 years AGO

option 1) 3 km/hr and 8 km /hr
my solution is based on check by option...
for upstream :
speed of man = speed of man - rate of current
= 8 - 3 = 5 km/hr
for down stream :
speed of man= speed of man + rate of current
= 8+ 3= 11 km/hr
total time = up time + down time
= 30/5 + 44/11
6 + 4 = 10
so option satisfy the equation that's why Ans is (1)

Like? Yes (17) | No (4)  

Kushagra Tiwari   10 years AGO

Let rate upstream = x km/hr
and rate downstream = y km/hr.
Then,40/x +55/y = 13...(i)
and 30/x +44/y = 10
Multiplying (ii) by 4 and (i) by 3 and
subtracting ,we get:11/y = 1 or y = 11.
Substituting y = 11 in (i),
we get: x = 5.
Rate in still water =1/2(11+5) kmph =
8 kmph.
Rate of current=1/2(11-5)kmph = 3
kmph

Like? Yes (15) | No (5)  

suganya   10 years AGO

Let rate upstream = x km / hr and rate downstream = y km / hr.
Then, 40/x+ 55/y =13 ...(i)
and 30/x+44/y=10 ...(ii)
Multiplying (ii) by 4 and (i) by 3 and subtracting, we get :
11/y=1 or y=11.
Substituting y = 11 in (j), we get : x = 5.
threrefore Rate in still water =1/2(11+5)kmph=8kmph.
Rateofcurrent= 1/2(11−5)kmph=3kmph.

Like? Yes (12) | No (5)  

naina   10 years AGO

Let rate upstream = x km / hr and rate
downstream = y km / hr.
Then, 40x+ 55y =13 ...(i)
and 30x+44y=10 ...(ii)
Multiplying (ii) by 4 and (i) by 3 and
subtracting, we get :
11y=1ory=11.
Substituting y = 11 in (j), we get : x = 5.
\threrefore Rate in still water =
12(11+5)kmph=8kmph.
Rateofcurrent= 12(11−5)kmph=3kmph.

Like? Yes (14) | No (8)  

Vanika   10 years AGO

Let speed of man in still water= x km/h
rate of current = y km/h
so 30/(x-y) + 44/(x+y) = 10 .......eq(1)
40/ (x-y) + 55/ (x+y) = 13.......eq(2)
solving
x = 8 km/h
y = 3 km/h

Like? Yes (8) | No (2)  

Aastha   10 years AGO

let speed in upstream be u
speed in downstream be d
now,
a/c to question
30/u+44/d=10 .eq(1)
40/u+55/d=13...eq(2)
solving eq(1) & eq(2)
u=5km/hr
d=11km/hr
speed of current=c
speed of man=m
5=m-c
11=m+c
on solving
m=8,c=3

Like? Yes (10) | No (5)  

Inline Geek   10 years AGO

let speed of current and man in still water be y and x respectively

no solve these equetions

(30 / (x - y) ) + (44 / (x + y)) = 10

(40 / (x - y) ) + (55 / (x + y)) = 13

x = 8,
y = 3

Like? Yes (9) | No (5)  

Surya Srivastava   10 years AGO

equation is
30/x-y+44/x+y=10
now put the values given whenever it satisfies the equation
its the ans.

Like? Yes (5) | No (1)  

raushan kumar   10 years AGO

let the speed of man in still water be X
speed of current be Y
According to equation
30/X+Y + 44/X-Y =10
40/X+Y + 55/X-Y =13
by solving equation
X&Y=8&3 ans

Like? Yes (3) | No   

Premchander   10 years AGO

Let rate upstream = x km / hr and rate downstream = y km / hr.
Then, 40x+ 55y =13 ...(i)
and 30x+44y=10 ...(ii)
Multiplying (ii) by 4 and (i) by 3 and subtracting, we get :
11y=1ory=11.
Substituting y = 11 in (j), we get : x = 5.
\threrefore Rate in still water =
12(11+5)kmph=8kmph.
Rateofcurrent= 12(11−5)kmph=3kmph.

Like? Yes (4) | No (1)  

Anant Vardhan   10 years AGO

Downstream Speed = 11kmph = B + R
Upstream Speed = 5kmph = B - R
,where B= Speed of Man
R= Speed of River
Solve the above two equations.

Like? Yes (4) | No (1)  

Rashi Bansal   10 years AGO

let rate of upstream= x km/hr and rate of downstream= y km/hr
a.t.q.
30/x +44/y=10
40/x + 55/y=13
solving these equations x=5,y=11
rate of current=1/2(y-x)=3km/hr
rate in still water=1/2(y+x)=8km/hr

so option (1) is correct.

Like? Yes (5) | No (3)  

Shreya Tiwari   10 years AGO

Let rate upstream = x km/hr
and rate downstream = y km/hr.
Then,40/x +55/y = 13...(i)
and 30/x +44/y = 10
Multiplying (ii) by 4 and (i) by 3 and
subtracting ,we get:11/y = 1 or y = 11.
Substituting y = 11 in (i),
we get: x = 5.
Rate in still water =1/2(11+5) kmph =
8 kmph.
Rate of current=1/2(11-5)kmph = 3
kmph

Like? Yes (2) | No   

BHASKAR MANDAL   10 years AGO

let x be the speed of the man in still water, and y be the speed of stream.
we can write,
30/(x-y) + 44/(x+y) = 10
40/(x-y) + 55/(x+y) = 13

on solving, x=8 and y= 3
it can be directly found out by substituting the values in the equation.

Like? Yes (3) | No (1)  

Arnab Mukherjee   10 years AGO

let rate in upstream is xkm/hr and downstream is ykm/hr
40/x+55/y=13 and 30/x+44/y=10
multiplying this equation we get 11/y=1 y= 11

and substitute it any equation we get x=5
rate in still water=(11+5)/2=8 kmph
rate of the current=(11-5)/2=3 kmph

Like? Yes (2) | No   

Suganya   10 years AGO

LET X=rate of current
Y=speed of man in still water

30/x+44/y=10
40/x+55/y=13
Solving these two equations
x=5
y=11
rate of current =(x-y)/2=3km/hr
speed in still water=(x+y)/2=8km/hr

Like? Yes (5) | No (3)  

ADARSH GAURAV   10 years AGO

1 is the correct option

Like? Yes (2) | No   

Abhimanyu kumar   10 years AGO

30/(x-y) +44/(x+y) =10........(i)
40/(x-y) + 55/(x+y) =13 ......(ii)
solve &get x=8, y=3

Like? Yes (3) | No (1)  

pawan kumar   10 years AGO

Let. Upstream speed = U Downstream speed = D
so, 30D+44U = 10UD
40D+55U = 13UD
Hence, U=5 , D=11
so, speed of curr=3kmph ,
speed of man=8kmph

Like? Yes (2) | No   

Abhishek Tiwari   10 years AGO

let the speed upstream be: x km/hr and speed downstream be : y km/hr
now,
time=dist./speed
so, 30/x+44/y=10......................eqn(1)
and 40/x+55/y=13....................eqn(2)
on solving both, we get :
x=5 km/hr and y=11 km/hr
now, speed of man in still water will be:
1/2*(y+x)=8 km/hr
and rate of current will be : 1/2*(y-x) = 3 km/hr
so, option (1) is correct

Like? Yes (2) | No (1)  

neha kumari   10 years AGO

30/x+44/y=10
40/x+55/y=13

Like? Yes (1) | No   

somaiah tummala   10 years AGO

let upstream=x km/hr,downstream=y km/hr
then 40x+55y=13 ---(1)
and 30x+44y=10 ---(2)
multiply eqn(2) with 4 & eqn(1) with 3
we get x=5 and y=11
therefore rate in still water=12(11+5)=8kmphr
rate of current=12(11-5)=3kmphr

Like? Yes (2) | No (1)  

ANTRISH MISHRA   10 years AGO

if rate of US=x;
and rate of DS=y;
then,
(30/x) + (44/y) =10..........(1)
(40/x) + (55/y) =13...........(2)
solving 1 and 2 we get x=5,y=11
now rate in current water=1/2(11-5)=3 kmph
and rate in still water = 1/2(11+5)=8 kmph

Like? Yes (1) | No   

prabhat   10 years AGO

let rate of stream =x km/h and rate downstream =y km/h
30/x+44/y=10 and 40/x+55/y=13
then solve equation the value of x =5 and y=11
rate in steel water =1/2(11-5)=8
rate of current=1/2(11-5)=3

Like? Yes (2) | No (1)  

Ankit Pandey   10 years AGO

Let us suppose upstream rate= x km/hr
downstream rate = y km/hr
so,
(30/x)+(44/y)=10 .........(1)
(40/x)+(55/y)=13 .........(2)
on solving both, we get y=11 km/hr
and x= 5 km/hr
so current rate=1/2(11-5)=3 km/hr
and rate of man in still water= 1/2(11+5)= 8 km/hr

Like? Yes (1) | No   

shiv   10 years AGO

rate updtream=x
rate downstream=y
30/x + 44/y =10
40/x + 55/y=13
on solving , we get
x=5,y=11
rate of current=(11-5)/2 =3
spped of men in still water =(11+5)/2 =8

Like? Yes (1) | No   

Shashi nath jha   10 years AGO

Ans

Like? Yes (3) | No (2)  

Mahendra Jakka   10 years AGO

b, s speeds of boat and stream
from given data- (30/b-s)+(44/b+s)=10
(40/b-s)+(55/b+s)=13
37b-7s=5(b2-s2)
95b-15s=13(b2-s2)
solving we get b=8kmph & s=3 kmph

Like? Yes (1) | No   

Ritesh Kumar   10 years AGO

option matching

Like? Yes (2) | No (1)  

V.Latha   10 years AGO

rate of upstream = x km/hr,
rate of downstream = y km/hr
40x+55y = 13 ---->(i)
30x+44y = 10 ---->(ii)
x = 5 and y = 11
Rate in still water = (11+5)/2 =16/2 = 8km/hr
rate of current = (11-5)/2 = 6/2 = 3km/hr

Like? Yes (1) | No   

Bharat Ratna   10 years AGO

let sepeed upstream=x downstream=y
30/x+44/y=10 and 40/x+55/y=13
solving x=5 y=11 speed in still water =1/2(x+y) =8km/h speed stream=1/2(y-x)= 3km/h

Like? Yes (2) | No (1)  

mithilesh kumar   10 years AGO

let upstraem=x doenstream=y
so 30/x+44/y=10 .....(1) sinse t=distance/speed
and
40/x+55/y=13.....(2)
solving these 2 eqn we get x=5 and y=11
now rate of current=(11-5)/2=3km/h
and speed of man=(11+5)/2=8km/h

Like? Yes (1) | No   

dhanaseelan   10 years AGO

lets take speed of the downstream is a and upstream is b
(30/a)+(44/b)=10
(40/a)+(55/b)=13
by solving these two equations you will get a=11, b=5
so rate of the current=(a-b)/2=3 kmph
speed of the man=(a+b)/2=8 kmph

Like? Yes (1) | No   

ANKUR ANAND   10 years AGO

by option checking we can get the result:
30/(8-5)+ 44/(8+3)=10
and 40/(8-5) +55/(8+5)=13

answer is 1)

Like? Yes (3) | No (2)  

Mello   10 years AGO

u=man speed, v=current
take upstream speed=u-v, downstream=u+v
so by time=distance/speed
and taking u-v=n and u+v=m we get
30n+44m=10
40n+55m=13
solve two eqn get values of m & n
then substitute it fr getting values of u & v

Like? Yes (2) | No (1)  

SOURABH   10 years AGO

let speed of man in still water be x and speed of current be y
speed in upstream=x-y
speed in downstream=x+y
30/(x-y)+44/(x+y)=10
40/(x-y)+55/(x+y)=13

Like? Yes (3) | No (2)  

veeranjaneyulu   10 years AGO

30/x+44/y=10,40/x+55/y=13
solve these two equations we get x=5,y=11
then in stillwter=1/2(x+y)=8
rate of current=1/2(x-y)=3 its not negative

Like? Yes (1) | No   

Anuj Tiwari   10 years AGO

let rate upstream=x & rate downstream=y

30/x + 44/y =10 ...(1)
40/x + 55/y =13 ...(2)
solving 1 & 2 we get,
x=5 y=11
now,
rate of current=(11-5)/2=3
speed of man in still water=(11+5)/2=8

Like? Yes (2) | No (1)  

Ravi Kumar   10 years AGO

let x=1/D and y=1/U
44x+30y=10
55x+40y=13
solving D=11 , U=5
rate of current = (D-U)/2=3
speed of man in still water =(D+U)/2=8

Like? Yes (2) | No (1)  

kadurla siva teja   10 years AGO

v-u=30/t1 v+u=4/t2 t1+t2=10
v-u=40/t1 v+u=55/t2 t1+t2=13
by solving we get v=8 u=3

Like? Yes (1) | No   

madhuri   10 years AGO

let downstream speed is d km/h
and upstream speed is u km/h
then
30/u + 44/d = 10
40/u + 55/d = 13
on solving,
u=5 km/h
d=11 km/h
So rate of current=1/2*(d-u)=1/2*(11-5)=3km/hr
and speed in still water=1/2*(u+d)=1/2*(5+11)=8km/hr

Like? Yes (1) | No   

Dark Knight   10 years AGO

let the upstream be x and downstream be y
then
40/x+55/y=13-------1
30/x+44/y=10-------2
solving we will get x as 5 and y as 11
rate of stream 1/2(11-5)=3km
rate at still h20=1/2(11+5)=16

Like? Yes (1) | No   

Chandra chur anand   10 years AGO

30/x+44/y=10 and 40/x+55/y=13
by equating both equation we get x=5 km/hhr and y=11 km/hr
now speed of man=(11+5)/2=8 km/hr
and rate of current=(11-5)/2=3km/hr
hence option 1 is correct

Like? Yes (1) | No   

amit vijayvargiya   10 years AGO

30u+44d=10
40u+55d=13
so u=5, d=11
rate of current=(d-u)/2;
speed of man in still water=(d+u)/2
rate of current=3
speed of man in still water=8

Like? Yes (1) | No   

Surit Datta   10 years AGO

Let rate of current is y and the speed of the man in still water is x
so according to the given data we say,
30/(x-y) + 44/(x+y) = 10
40/(x-y) + 55/(x+y) = 13
solving the above two we get,
x = 3
y = 8
So rate of current is 3km/hr
and
the speed of the man in still water is 8km/hr.
That's it..

Like? Yes (1) | No   

Biswajit Malakar   10 years AGO

let rate of upstream = x km/hr and downstream y km/hr
then
30/x + 44/y = 10 -(i) and 40/x + 55/y = 13 -(i)
multiplying 4 in (i)
and 3 with (ii)
we get y=11,x=5
rate in still water 1/2(11+5)=8 km/hr
rate of current 1/2(11-5)=3 km/hr

Like? Yes (1) | No   

srija   10 years AGO

30/x+44/y=10
40/x+55/y=13
after solving we get x=11,y=5
rate in stillwater=1/2(11+5)=8kmph
rate of current=1/2(11-5)=3kmph

Like? Yes (1) | No   

Y V S Chandrakanth   10 years AGO

30/(u-v)+44/(u+v)=10

40/(u-v)+55/(u+v)=13

By Verification of options we will get option (1).

Like? Yes (1) | No   

Avinash Aryan   10 years AGO

1

Like? Yes (1) | No   

ravi prakash   10 years AGO

30/a+44/b=10;
40/a+55/b=13;
here a=(x-y)down stream ,x=speed of current,y=of man
b=(x+y)upstream
on solving x=3
y=8

Like? Yes (1) | No   

suresh   10 years AGO

let upstream is x and downstream is y
30/x+44/y=10---------1
40/x+55/y=13---------2
now multiply 1 with 4 & multiply 2 with 3
then we get y=11 substituting in 1 we get x=5
then rate of current is=1/2(down stream-up stream)
=1/2(11-5)=3
speed of man=1/2(11+5)=8

Like? Yes (1) | No   

Basil Sufyan   10 years AGO

this will be solved by simultanious equation
30/(m-s)+44/(m+s)=10.... eqn 1
40/(m-s)+55(m+s)=13... eqn 2

where m=speed of man in still water and s =speed of stream
solve it and you will get the answer

Like? Yes (1) | No   

Souvik Datta   10 years AGO

Let rate upstream = x km/hr and rate downstream = y km/hr
then, 40/x+55/y=13 ... (i) and 30/x+44/y=10 ... (ii)
after solving this we get y=11, x=5
rate of current =1/2(11-5)= 3 kmph
man in still water= 1/2(11+5)= 8 kmph

Like? Yes (1) | No   

siddharth prakash singh   10 years AGO

let upstream=x, down stream=y
40/x+55/y=13
30/x+44/y=10
solving both. x=5 and y=11
so,rare in still water=(11+5)/2=8
rate of current=(11-5)/2=3

Like? Yes (1) | No   

khushboo goenka   10 years AGO

let upstream speed=x , downstrm=y.
thn in 10 hrs, time by upstrm=30/x
tym by dwn=44/y
30/x =+44/y=10
similarly, 40/x + 55/y =13
on solving these 2 eqtns we get x=5, y=11
now speed of man - speed of stil water=5
speed of man + speed of water = 11
on solving, man speed = 8 km/hr nd still water rate = 3 km/hr

Like? Yes (1) | No   

MANU   10 years AGO

let speed in upsterm =x km/h and down stream =y km/h;
40/x+55/y=13;
30/x+44/y=10
solving we get
x=5 and y=11;
so speed of man on still water=8 kn/h;
speed of current=3 km/h;

Like? Yes (1) | No   

Ayush Chawla   10 years AGO

let speed upstream be x kmhr and downstream be y kmhr
40/x + 55 /y = 13 -- (i)
30/x + 44/y = 10 -- (ii)
multiple (ii) by 4 and (i) by 3 and subtract we get y/11=1 or y=11
thus x =5
rate in still water of man = 1/2(11+5) = 8 km/hr
rate of current = 1/2(11-5)=3 km/hr

Like? Yes (1) | No   

Dr.Dipin Singh   10 years AGO

30/5+44/11=10
40/5+55/11=13

Like? Yes (1) | No   

Mahesh   10 years AGO

Let take his upstream speedd and down stream speed as x and y
30/x+44/y=10
40/x+55/y=13
lets take 1/x and 1/y as a and b respectively
By solvinf the two equations we will get a as 1/5 and b as 1/11
x and y are 5 and 11
So, speed of the stream and boat are 3 and 8 respectively
Correct answer is A

Like? Yes (2) | No (2)  

NAVEEN KUMAR   10 years AGO

let rate of up stream=x km/h and downstream= y km/h
then,30x+44y=10----(1)
40x+55y=13---(2)
after solving x=1/5
y=1/11
hence,upstram speed=5km/h
downstream=11km/h
rate of current=(11-5)/2=3km/h
speed of the man in still water=(11+5)/2=8km/h
option(1)

Like? Yes (5) | No (5)  

Ravi Bhalani   10 years AGO

Let rate upstream = x km / hr and rate downstream = y km / hr.
Then, 40/x+ 55/y =13 ...(i)
and 30/x+44/y=10 ...(ii)
Multiplying (ii) by 4 and (i) by 3 and subtracting, we get :
11/y=1 or y=11.
Substituting y = 11 in (j), we get : x = 5.
threrefore Rate in still water =
1/2(11+5)kmph=8kmph.
Rateofcurrent= 1/2(11−5)kmph=3kmph.

Like? Yes (2) | No (2)  

Sohidul Islam   10 years AGO

Let x and y be the speed of the boat in still water and speed of the stream respectively
So we get the following 2 equations
44/(x+y) +30/(x-y)=10 -------------[1]
55/(x+y)+40/(x-y)=13 --------------[2]
Solving this equations we get x=8,y=3........hence option 1

Like? Yes (2) | No (2)  

MOHIT GARG   10 years AGO

Let rate upstream = x km / hr and rate downstream = y km / hr.
Then,  40x+ 55y   =13   ...(i)
and   30x+44y=10       ...(ii)
Multiplying (ii) by 4 and (i) by 3 and subtracting, we get : 
11y=1ory=11.
Substituting y = 11 in (j), we get : x = 5.
\threrefore Rate in still water =
12(11+5)kmph=8kmph.
Rateofcurrent= 12(11−5)kmph=3kmph.

Like? Yes (4) | No (4)  

Abhishek Vishwakarma   10 years AGO

Let rate upstream = x km/hr
and rate downstream = y km/hr.
Then,40/x +55/y = 13...(i)
and 30/x +44/y = 10
Multiplying (ii) by 4 and (i) by 3 and
subtracting ,we get:11/y = 1 or y = 11.
Substituting y = 11 in (i),
we get: x = 5.
Rate in still water =1/2(11+5) kmph =
8 kmph.
Rate of current=1/2(11-5)kmph = 3
kmph

Like? Yes (2) | No (2)  

Narasapu Hari prasad   10 years AGO

option 1 is correct
let x be the speed of man in still water and y is current speed
from given data
30/(x-y)+44/(x+y)=10
74x-14y=10x^2-10y^2---------------(1)
40/(x-y)+55/(x+y)=13
95x-15y=13x^2-13y^2---------------(2)
solve (1) and(2) you will get
x/y=32/12=8/3
so x=8,y=3
speed of man is 8 and current water speed is 3

Like? Yes (1) | No (1)  

anandhakumar   10 years AGO

ans is option 1

Like? Yes (2) | No (2)  

Pradeep Saw   10 years AGO

Let rate upstream = x km / hr and rate downstream = y km / hr.
Then, 40x+ 55y =13 ...(i)
and 30x+44y=10 ...(ii)
Multiplying (ii) by 4 and (i) by 3 and
subtracting, we get y=11.
Substituting y = 11 in (j), we get : x =
5.
Rate in still water =12(11+5)kmph=8kmph.
Rate of current= 12(11−5) kmph=3kmph

Like? Yes (3) | No (3)  

vikash kumar   10 years AGO

3km/h and 8km/h is the ans

Like? Yes (1) | No (1)  

Mogilipuri.Harish   10 years AGO

up to stream is =x km/hr
rate of downto stream= y km/hr
then 40/x+55/y=13 and 30/x+44/y=10
then we get x=5 and y=11
rate in still water =1/2(11+5)= 8 km/hr
rate of current =1/2(11-5)= 3 km/hr

Like? Yes (3) | No (3)  

Gitanjali K   10 years AGO

let, rate upstream = x km/hr
rate downstream = y km/hr

given, 30/x+44/y=10.....(1)
40/x+55/y=13 ...(2)

solving eq(1)&(2)
we get x=5, y=11

so speed of man in still water=(11+5)/2=8km/hr
rate of current=(11-5)/2=3km/hr
hence is the answer..

Like? Yes (2) | No (3)  

S.SHAFI   10 years AGO

Let rate upstream = x km/hr
and rate downstream = y km/hr.
Then,40/x +55/y = 13...(i)
and 30/x +44/y = 10
Multiplying (ii) by 4 and (i) by 3 and subtracting ,we get:11/y = 1 or y = 11.
Substituting y = 11 in (i),
we get: x = 5.
Rate in still water =1/2(11+5) kmph = 8 kmph.
Rate of current=1/2(11-5)kmph = 3 kmph

Like? Yes (2) | No (3)  

PAWAN KUMAR   10 years AGO

let the spped of man in still water be x km/h and the speed of current be y km/h.
then, 30/(x-y) + 44/(m+s) = 10
and 40/(x-y) + 55/(x+y) = 13
on solving, we get x= 8km/h and y= 3 km/h. Ans.

Like? Yes (1) | No (2)  

nishu kumar   10 years AGO

let rate in upstream =x km/h
rate downstrean=y km/h
then,
30/x+44/y=10......(1)
40/x+55/y=13.....(2)
solving both equations,we get
x=5km/h
y=11km/h
then
rate of current=1/2*(downstream speed-upstream speed)
=1/2*(11-5)
=3 km/h.
apeed of man in still water=1/2*(downstream speed+upstream speed)
=1/2*(11+5)
=8km/h

Like? Yes (1) | No (2)  

Urvashi Jain   10 years AGO

let rate upsream =xkm/hr and downstream y km/hr
30/x+44/y=10...1
40/x+55/y=13...2
x=5 y=11
rate of current=1/2(11-5)=3km/hr
rate in still water=1/2(11+5)=8km/hr

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sudhakar   10 years AGO

option 1)3 km/hr and 8 km/hr

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J.Praveen Kumar   10 years AGO

from problem we can have 2 equations:
sb=speed of boat(man)
sw=speed of water(current)
1) : (30/(sb-sw) ) + (44/(sb+sw)) = 10

2) : (40/(sb-sw))+(55/(sb+sw)) = 13

by solving these equations we have

12sb=32sw
substitute option 1 we have answer.

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kumar   10 years AGO

eqn will be
30/(x-y) +44/(x+y) =10
and
40/(x-y)+55(x+y)=13

since you have options then check for eqn 1st if satisfy then check for eqn 2
so first opn
3,8
30/5+44/11=10 satisfy
for eqn 2
40/5+55/11=13
hence ans 1)

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deepak kumar   10 years AGO

in up stream speed 8-3=5km/hr so time taken in up stream 30/5=6hr and during down stream speed=11km/hr and time = 44/11=4hr.total time=6+4=10 hr.

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Neel Patel   10 years AGO

Check by option

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Kumar Vishal   10 years AGO

1

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Supriya Sinha   10 years AGO

Speed of man+ speed of stream==11

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Tark Patel   10 years AGO

Let rate upstream = x km/h and rate downstream = y km/h

Given-> 40/x + 55/y = 13 and 30/x + 44/y = 10
Solving this two expressions we get x = 5 km/h and y = 11 km/h

rate in still water = 1/2 ( 11 + 5 ) = 8 km/h
rate of current = 1/2 ( 11 - 5 ) = 3 km/h

Like? Yes (1) | No (2)  

Amit Verma   10 years AGO

let the speed of man be x km/hr
and that of current be y km/hr
so
time taken to go upstream be t1 hrs and downstream (10-t1) hrs
similarly for second case t2 and 10-t2

(x-y)*t1+(x+y)(10-t1)=74
(x-y)*t2+(x+y)(10-t2)=95
now refer to options only first option satisfies it
crrent -= 3km/hr and man =8km/hr
because when we downstream 44 km of distance is travelled which is multiple of 4 and 11
so first option satisfies it

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sandeepsingh   10 years AGO

find by solving

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saimeera   10 years AGO

let man's speed be x;
and rate of current be y;

(30/(x-y))+(44/(x+y))=10
(40/(x-y))+(55/(x+y))=13

solving for x and y,
x=8 and y=3

Like? Yes (1) | No (2)  

Shashank Kapoor   10 years AGO

let upstream=x km/hr
let downstream=y km/hr

then 30/x+44/y=10 (i)
and 40/x +55/y=13 (ii)

solving (i) and (ii)
x= 5km/hr and y= 11km/hr

rate in still water= 1/2(11+5)=8 and rate of current= 1/2(11-5)=3.
so ans is option 1

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Harshad    10 years AGO

Let rate upstream = x km / hr and rate downstream = y km / hr.
Then, 40/x+ 55/y =13 ...(i)
and 30/x+44/y=10 ...(ii)
Multiplying (ii) by 4 and (i) by 3 and subtracting, we get :
11/y=1 or y=11.
Substituting y = 11 in (j), we get : x = 5.
threrefore Rate in still water =
1/2(11+5)kmph=8kmph.
Rateofcurrent= 1/2(11−5)kmph=3kmph.

Like? Yes (1) | No (3)  

DIPAK TIWARI   10 years AGO

30/(u-v) + 44/(u+v) =10........(i)
40/(u-v) + 55/(u+v) =13........(ii)
u=8 & v=3
option 1

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raghu   10 years AGO

check with options.....
x= speed in upstream, y=speed in down stream.....
30/x + 44/y =10 and 40/x + 55/y =13
check x and y with different values. you will get the answer
(or)
solve those equations above you get x=5 and y=11...

rate of current or speed of stream= 1/2(y-x)
=1/2(6)
=3 km/hr
speed of the man in still water=1/2(x+y)
=8 km/hr

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RAKESH   10 years AGO

30/ x-y + 44/ x+y = 10

40/ x-y + 55/ x+y = 13

x=8,y=3

Like? Yes (2) | No (5)  

lakshmi nalluri   10 years AGO

upstream be x n downstream be y
then,30/x+44/y=10
and 40/x+55/y=13
on solving,x=5, y ll be 11
and rate in still water=(11+5)/2=8
rate of current=11-5)/2=3

Like? Yes (2) | No (6)  

santosh kumar patel   10 years AGO

let rate upstrem =x km/h and rate downstream=y km/h
then, 30/x+44/y=10...............1
and 40/x+55/y=13.................2
solve the equation 1 and 2
we get x=5 and y=11
so rate of current water=1/2(11-5)=3 km/h
and rate of still water=1/2(11+5)=8 km/h

hence ans: rate of current water = 3 km/h
rate of still water = 8 km/h

Like? Yes (1) | No (6)